[问题/Issue] 章节10.3.3：ModuleNotFoundError: No module named 'flask' #255
Description
1. 遇到问题的章节 / Affected Chapter
Chapter 10.3.3
2. 问题类型 / Issue Type
依赖问题 / Dependency Issue
3. 具体问题描述 / Problem Description
python 09_A2A_Server.py
✅ 研究员Agent服务已启动在 http://localhost:5000
Exception in thread Thread-1 (start_server):
Traceback (most recent call last):
File "/Users/tiansiyuan/Downloads/projects/hello-agent/.venv/lib/python3.12/site-packages/hello_agents/protocols/a2a/implementation.py", line 62, in run
from flask import Flask, request, jsonify
ModuleNotFoundError: No module named 'flask'
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
File "/Users/tiansiyuan/.local/share/uv/python/cpython-3.12.10-macos-aarch64-none/lib/python3.12/threading.py", line 1075, in _bootstrap_inner
self.run()
File "/Users/tiansiyuan/.local/share/uv/python/cpython-3.12.10-macos-aarch64-none/lib/python3.12/threading.py", line 1012, in run
self._target(*self._args, **self._kwargs)
File "/Users/tiansiyuan/Downloads/projects/hello-agent/09_A2A_Server.py", line 35, in start_server
researcher.run(host="localhost", port=5000)
File "/Users/tiansiyuan/Downloads/projects/hello-agent/.venv/lib/python3.12/site-packages/hello_agents/protocols/a2a/implementation.py", line 64, in run
raise ImportError(
ImportError: A2A server requires Flask. Install it with: pip install flask安装 hello-agents 所需版本时遇到下面的警告：
uv pip install "hello-agents[protocol]==0.2.2"
Using Python 3.12.10 environment at: /Users/tiansiyuan/Downloads/projects/hello-agent/.venv
Resolved 69 packages in 2.95s
Prepared 2 packages in 3.75s
Uninstalled 2 packages in 131ms
Installed 2 packages in 8ms
- hello-agents==0.2.8
+ hello-agents==0.2.2
- numpy==2.3.5
+ numpy==1.26.4
warning: The package `hello-agents==0.2.2` does not have an extra named `protocol`4. 问题重现材料 / Reproduction Materials
python 09_A2A_Server.py 错误信息：
✅ 研究员Agent服务已启动在 http://localhost:5000
Exception in thread Thread-1 (start_server):
Traceback (most recent call last):
File "/Users/tiansiyuan/Downloads/projects/hello-agent/.venv/lib/python3.12/site-packages/hello_agents/protocols/a2a/implementation.py", line 62, in run
from flask import Flask, request, jsonify
ModuleNotFoundError: No module named 'flask'
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
File "/Users/tiansiyuan/.local/share/uv/python/cpython-3.12.10-macos-aarch64-none/lib/python3.12/threading.py", line 1075, in _bootstrap_inner
self.run()
File "/Users/tiansiyuan/.local/share/uv/python/cpython-3.12.10-macos-aarch64-none/lib/python3.12/threading.py", line 1012, in run
self._target(*self._args, **self._kwargs)
File "/Users/tiansiyuan/Downloads/projects/hello-agent/09_A2A_Server.py", line 35, in start_server
researcher.run(host="localhost", port=5000)
File "/Users/tiansiyuan/Downloads/projects/hello-agent/.venv/lib/python3.12/site-packages/hello_agents/protocols/a2a/implementation.py", line 64, in run
raise ImportError(
ImportError: A2A server requires Flask. Install it with: pip install flask
5. 补充信息 / Additional Information
No response
确认事项 / Verification
- 我已阅读过相关章节的文档 / I have read the relevant chapter documentation
- 我已搜索过现有的Issues,确认此问题未被报告 / I have searched existing Issues and confirmed this hasn't been reported
- 我已尝试过基本的故障排除(如重启、重新安装依赖等) / I have tried basic troubleshooting (restart, reinstall dependencies, etc.)